1. Field of the Invention
The present invention relates to an arrangement in substantially rectangular, self-supporting, preferably corrugated roofing tiles to be mounted upon supporting purlins or horizontal laths, each tile being positioned with an overlap with respect to the adjacent tiles both in the horizontal direction and along the line of fall of the roof and being provided with cut-outs at two diagonally opposite corners in order to avoid the need of superimposing the two middle tiles of a crossing formed by four tile corners, while allowing a variation in the overlap distance in the direction of the line of fall of the roof.
2. Description of the Prior Art
When laying roofing tiles or roofing plates with an overlap both in the horizontal direction and in the direction of the line of fall of the roof, joining or overlap crossings occur in the places where the corners of four tiles or plates are superimposed. This is no serious disadvantage when working with thin roofing plates, such as corrugated metal plates, but when the tiles consist of burnt clay, asbestos cement, ceramic material or the like and have a thickness of 4 to 5 mm or more, the situation is different. To enable the two middle corners in the crossing to be situated alongside each other in the same plane instead of being superimposed, it is known to provide two diametrically opposite corners with matching cut-outs, the corner being e.g. simply cut off by an oblique cut.
When roofing with such tiles a first horizontal row of tiles is usually laid at the eaves. Then a second horizontal row of tiles is laid so as to provide a certain overlap with said first layer, etc. until reaching the ridge of the roof, which finally is covered with especial ridge tiles or the like. If the distance between the eaves and the ridge is not a multiple of the pattern height (height of the tile less the overlap distance), the tiles in the top row have to be cut. However, to avoid such cutting it is moreover known (see Austrian Pat. No. 336,851) to alter the overlap distance to such an extent that on any roof not having too small a distance between the eaves and the ridge a roofing using an integer number of tile heights can be obtained. When the tiles are laid with an overlap distance smaller than the maximum possible overlap distance, the tiles having obliquely cut corners will be spaced from each other and thus form a channel or a passage therebetween, up through which precipitation may be pressed under unfavourable wind conditions. According to Austrian Pat. No. 336,851 it is thus known to lengthen each tile somewhat to extend below the lower obliquely cut corner, so that the inlet to this passage is covered to a certain degree. Still a reduced sealing to penetrating precipitation must be expected.